Neural targets that control thermogenesis, behavior, sleep, and mood are often suffering from pro-inflammatory cytokines that are released by activated macrophages and monocytes during infection. Within the central systema nervosum production of cytokines has been detected as a result of brain injury, during viral and bacterial infections, and in neurodegenerative processes. Neuroimmunology may be a field combining neuroscience, the study of the systema nervosum, and immunology, the study of the system . Neuro immunologists seek to raised understand the interactions of those two complex systems during development, homeostasis, and response to injuries.